Ester of acetylphenylglycinortho carbonic acid.



UNITED STATES PATENT OFFIOE BERNI-IARD I'IEYMANN, OF ELBE RFELD, GERMANY, ASSIGNOR TO THE FAR- BENFABRIKEN OF ELBERFELD COMPANY, OF NEVVYORK.

ESTER OF ACETYLPHENYLGLYCINORTHO C ARBONIC ACID.

SiIPIECZIFICAZIION forming part of Letters Patent No. 647,263, dated April 10, 1900.

Application filed January 16 1900. Serial No. 1,655. (No specimens-l I /COCH3 N\ on ooon COOR , (R meaning an alkyl radical, such as ethyl, 'methyl, or the like,) represent very valuable starting materials for the production of indigo. These esters, which were unknown up to the present time, can be obtained by subjecting the neutral esters of phenylglycinortho carbonic acid to the action of acetylizing agents, such as acetyl chlorid or the like. The new bodies represent white crystalline substances soluble in ether, benzene,and alcohol. They are characterized by the fact that they yield an indigo leuco compound in a very profitable manner if they are mixed with dry caustic alkalies and heated on a water-bath. In carrying out my new process practically I can proceed as follows, the parts being by weight: A mixture of twenty-five parts of the diethylester of phenylglycinortho carbonic acid and sixteen parts of acetylchlorid is heated for about one hour on a water-bath in a vessel provided with a reflux condenser. Subsequently the excess of acetyl chlorid is distilled off and the oily residue thus obtained, which soon transforms into a crystalline mass, is washed with cold water. On dissolving this mass in ether and adding ligroin to the resulting solution the diethylester of the acetylphenylglycinortho carbonic acid separates in the shape of cubic crystals, which are isolated by filtration and dried. The new ester thus obtained, having the formula 00. on N 3 CIEH/ on, 00 00,11,

' contains an indigo leuco compound. On diluting this melt with water and causing air to pass through the liquid this leuco compound is transformed into indigo.

The process proceeds in an analogous manner ifinstead of the neutral ethyl ester other alkyl esters of phenylglycinortho carbonic acid are employed in the above example. Thus, for instance,on using the dimethyl ester of phenylglycinortho carbonic acid the neutral dimethyl ester of acetylphenylglycinortho carbonic acid is obtained in the shape of a white crystalline substance melting at 83 centigrade.

Having now described my invention and in what manner the same is to be performed, what I claim as new, and desire to secure by Letters Patent, is.

1. As new articles of manufacture the new esters of the general formula oo.oH,

OGI714/ oH,.oooR

It is soluble in ether,

2. As a new article of manufacture the the fact that it yields an indigo leuco comdiethylester of acetylphenylglycinortho carpound if it is heated with dry caustic alkabonic acid having the formula lies on a water-bath, substantially as herein- I 5 CO CH before described. 5 N 3 In testimony whereof I have signed my name in the presence of two subscribin wit- O H CH2 CO'OO2H5 nesses'. b

OO.OO H BERNHARD I-IEYMANN.

10 which is a White crystalline substance, solu- Witnesses:

ble in ether, benzene and alcohol, melting at OTTO KONIG,

62 Centigrade and which is characterized by F. A. RITTERSHAUS. 

